The invention relates to radio-opaque polymeric compositions which can be used as covering compositions for polymeric, ceramic and metal objects. Additionally, this invention relates to radio-opaque objects and methods for rendering objects radio-opaque.
The ability to render objects radio-opaque is important in several fields. It is especially important in the medical field. For example, medical devices which are radio-opaque enable easy radiological localization of such devices during medical procedures and post-operative follow-ups. In the industrial field there are many applications in which it is important to render devices radio-opaque in order to enable differentiation or to shield objects from X-rays.
Current methods of rendering objects radio-opaque involve compounding materials like barium sulfate (i.e., Ba SO4) into the objects; or plating/ion sputtering silver or gold onto the objects. It also is conventional for many medical device polymers to be filled with barium or bismuth radio-opaque compounds. Recently, radio-opaque paints and inks with barium sulfate or silver powders physically trapped in the composition have been proposed. Lead is also used in non-medical applications, typically in plated form or compounded into ceramics.
There are several disadvantages with the current methods of rendering objects radio-opaque. In particular, medical devices treated with the current methods have low bio-compatibility and may be toxic to tissues. Additionally, when the ion deposition is used on stents, the likelihood of restenosis increases. Other disadvantages with the current methods in the medical and the industrial fields include toxicity, galvanic corrosion, high economic cost, undesirable changes in the physical and electromagnetic properties of the devices and cumbersome processes in producing the devices. Additionally, current methods of shielding objects from X-rays are impractical and expensive.
Accordingly, it is one of the purposes of this invention, among others, to provide coverings and primers which will render objects radio-opaque without the disadvantages found in the prior art.
The present invention provides a radio-opaque composition including a polymer or monomer, wherein the polymer or monomer has a non-leachable radio-opaque moiety. The non-leachable radio-opaque moiety is covalently attached to the polymer or monomer.
Examples of a radio-opaque moiety include a halogenated aromatic compound with an attached reactive functional group. Examples of halogenated aromatic compounds include aromatic tri-iodides, aromatic tri-bromides, aromatic tri-fluorides and aromatic tri-chlorides. Examples of attached reactive functional groups include a hydroxyl, a carboxyl, an amine, an amide, a carbonyl, a thiol, an allyl, a vinyl or an anhydride group.
Further examples of the radio-opaque moiety include an amidotrizoate, an iothalamate, an iohexol, an iopamidol, an iopromide, ioxaglic acid, an iopadate, an iotroxate or an ioxaglate. Further examples of the radio-opaque moiety include Iobenguane, Iobenzamic Acid, Iocarmic Acid, Iocetamic Acid, Iodamide, Iodipamide, Iodixanol, Iodized Oil, Iodoalphionic Acid, p-Iodoaniline, o-Iodobenzoic Acid, lodochlorhydroxyquin, o-Iodohippurate Sodium, o-Iodophenol, p-Iodophenol, Iodophthalein Sodium, Iodopsin, Iodopyracet, Iodopyrrole, Iodoquinol, Iofetamine 123I, Ioglycamic Acid, Iohexol, Iomeglamic Acid, Iopamidol, Iopanoic acid, Iopentol, Iophendylate, Iophenoxic Acid, Iopromide, Iopronic Acid, Iopydol, Iopydone, Iothalamic Acid, Iotrolan, Ioversol, Ioxaglic Acid, Ioxilan, or Ipodate.
The polymer or monomer preferably has at least one reactive functional group. Examples of reactive functional groups are an isocyanate, an isothiocyanate, an ester, an aldehyde, an N-hydroxysuccinimide ester, an epoxide, a carboxylic ester, a tresylate, an anhydride, an alkyl halide, a carboxylic acid, a haloketone, an alkene, an alkyne or an acyl chloride.
In one embodiment the polymer is a synthetic polymer. The synthetic polymer can be a polymer blend, alloy, homopolymer, random copolymer, block copolymer or graft copolymer. The polymer blend, alloy, random copolymer, block copolymer or graft copolymer includes poly(vinyl alcohol), poly(vinylpyrrolidone), poly(caprolactone), poly(hydroxybutarates), poly(caprolactams), poly(acrylamides), poly(terephthalate), poly(vinyl chloride), poly(propylene), poly(ethylene oxide), poly(acrylic acid), poly(propylene oxide), poly(styrene), poly(ethylene), poly(urethanes), silicone elastomers or combinations thereof. The polymer can be a homopolymer of the aforementioned polymers.
In another embodiment the polymer is a natural polymer. Examples of a natural polymer include a cellulose, chitosan, chitin, starch, hyaluronic acid, chondroitin sulfate, zanthan, guar gum; or an ether or an ester derivative thereof; or a block, a graft or random copolymer thereof; or a blend thereof.
Examples of the monomers of the present invention include an acrylate, allyllic compound, amide, amine, anhydride, epoxide, isocyanate, methacrylate, silyl, thiol compound, thioisocyanate, vinyl compound, ester, acid chloride, acrolein or acryloylchoride.
Examples of the covalent attachment between the radio-opaque moiety and the polymer or monomer include an alkyl, amine, amide, anhydride, azide, carbamate, carbonate, carboxyl, ether, ester, imide, thiol, thiocarbamates, thioisocyante, urea or other covalent linkage.
In one embodiment the radio-opaque moiety can be covalently attached to the polymer or monomer by the use of heat, ultraviolet irradiation, gamma irradiation, an acidic initiator, a basic initiator, a peroxide initiator, a persulfate initiator or an azo initiator.
In one embodiment the composition of the present invention can further include at least one additional ingredient wherein the additional ingredient is releasable or non-releasable from the composition. In one embodiment the additional ingredient is a biologically active material. Examples of the biologically active material include a biostatic agent, a cytostatic agent, a radiation emitter, a biomolecule, an anti-inflammatory agent, an immunosuppressant or an antiseptic. Preferred biologically active materials include antibiotics and antithrombotic agents.
In one embodiment the composition has a low coefficient of friction when wetted with water or a water-containing substance. In this embodiment the composition can include a polyvinylpyrrolidone-polyurethane complex.
In one embodiment the composition can further include a solvent. The covalent linkage between the polymer or monomer and the radio-opaque moiety can be formed as the solvent is removed. Alternately, the covalent linkage can be formed during formulation of the composition.
In one embodiment the composition is a covering composition. Examples of covering compositions include coatings and primers. The primers of the present invention can be made of the same monomer or of a blend of monomers. The primers can include monomers which are covalently attached to an object by a covalent linkage; or they can include monomers which adhere to an object.
The present invention includes radio-opaque objects. In one embodiment the material of which the radio-opaque object is composed includes the composition of the present invention. In another embodiment the object is covered with a composition. The object can be a medical device. Examples of medical devices include catheters, guide wires, shunts, screws, pins, prostheses, plates, films, sponges, sutures, tubes, cannulas, balloons, needles, markers or stylets. A preferred medical device is a stent.
The present invention includes a method of rendering an object radio-opaque. In one embodiment the method includes: applying a covering composition to the object, wherein the covering composition includes a polymer or monomer. The polymer or monomer has a non-leachable radio-opaque moiety. The method can further include: placing the covering composition in a solvent, applying the covering composition in the solvent to the object and evaporating the solvent. Examples of application of the covering composition include spraying, dipping, plasma vapor deposition, flow coating, brushing or dabbing.
The present invention provides radio-opaque compositions and objects which avoid the disadvantages of current methods used to render objects radio-opaque. In particular, the present invention provides compositions that are bio-compatible; unlike medical devices treated with current methods which have low bio-compatibility and may be toxic to tissues. Additionally, the present invention avoids the increased likelihood of restenosis associated with current methods of ion deposition of stents. The present invention also avoids the problems associated with the current methods in the medical and the industrial fields including toxicity, galvanic corrosion, high economic cost, undesirable changes in the physical and electromagnetic properties of the devices and cumbersome processes in producing the devices. These and other advantages of the present invention will be appreciated from the detailed description and examples which are set forth herein. The detailed description and examples enhance the understanding of the invention, but are not intended to limit the scope of the invention.